Jennifer Garner is 43. She has three children, a busy acting career and she works with a number of charities. She also has the glowing, lineless skin of a 25-year-old, which makes her hectic schedule even more impressive. And she owes it all to her high school job.

“I’m very grateful that during my key sunning years — my teenage years — I was working in a theater all summer,” she says. “I have a sister who was a lifeguard out there just baking and roasting, and we didn’t know better.”

Now She Wears SPF — Every. Single. Day.

Garner says applying sunscreen is as much a ritual as brushing her teeth every morning. “I do it right away,” she says. “I have contacts — so I brush my teeth, put my contacts in and put my sunscreen on.”

Her go-to formula is Neutrogena Dry Touch Ultra Sheer, $13.99. “It doesn’t leave any residue or greasy feeling,” she says. “And makeup artists like it because it doesn’t mess with their work.”

But She Won’t Do Her Hair

On a regular day, Garner says she gets up before her kids to work out, and then quickly changes into “real-people clothes” before taking them to school — “because nobody needs to see me in a yoga pant all day,” she jokes. Still, she’s got no problem leaving the house without doing her hair. The two looks in her repertoire: wet or in a ponytail. “I don’t understand how to blow dry hair,” she says. When I ask her if hairstylists have tried to teach her any tricks over the years, she responds: “They know that their job is secure.”

She Has Tricks to Get Her Kids to Wear Sunscreen

I ask Garner if she’s crazy about her kids and sunscreen, and at first she tries to play it cool. “I’m on top of it, for sure,” she says. “I try not to be … yeah, I’m crazed. It’s non-negotiable.”

But she has certain tricks she uses to get them to sunscreen up. “Right now, what I’m doing is letting them choose a stick, a lotion, or a spray,” she says. “And the older ones can do it themselves with me watching to make sure [they don’t miss a spot] — because that’s the worst: when they do it, and they come home with a big sunburned spot.”

She Wants You to Get a Melanoma Check

The first Monday in May is Melanoma Monday, and there are plenty of opportunities to get a free skin cancer screening this month. At Target stores, for example, Neutrogena is offering free checks. “It’s so unsexy, and it’s something nobody in the world wants to talk about, much less do,” says Garner. “But just do it. Get it over with. And then you can pat yourself on the back for another year well done.”